In conventional radiation image conversion panels, the surface and/or the side-face of a vapor-deposited phosphor crystal, differing from the interior of the crystal, are exposed in various environments.
For instance, temperature change, or adsorption or desorption of inert gases occurs during vapor deposition and the subsequent steps are affected by a surface treatment or environmental moisture.
Specifically, there were produced problems that the crystal surface/side-face of a phosphor easily deteriorated in luminance and coalescence of columnar crystals due to the foregoing effects, resulting in deteriorated performance.
There have been few reports regarding the surface state which is considered to be essential in performance. There was a report defining the ratio of Cs to C, as described in, for example, JP-A No. 2005-24272 (hereinafter, the term JP-A refers to Japanese Patent Application Publication), which targeted reduction of staining on the crystal surface and was not studied of the composition of the crystal.